In less than 12 hours, Australia will officially reach a population milestone of 24 million people - this comes 17 years earlier than predicted with migration contributing more growth than the natural increase.
At 12.51am on Tuesday, The Bureau of Statistics' population clock is set to hit 24 million, with Australia adding a record extra million people every 3 years, according to social researcher and demographer Mark McCrindle.
'It's quite interesting to see how much it has taken demographers by surprise particularly when you go back to 1999 and the thought was that we wouldn't hit 24 million until 2033 - and we've achieved it 17 years early,' Mr McCrindle told Daily Mail Australia.
Doubling Australia's population - in pace with the world
Since 1968, It's taken 48 years to double Australia's population of 12 million.
Similarly, the global population has taken only slightly less time, 46 years, to double since 1970 when it was half of what it currently is at 7.3 billion.
A new million - in record time
There's no doubt that Australia's population is increasing at a rapid speed.
Even though both the birth rate and migration numbers have slowed, this is still a record time according to Mr McCrindle.
Australia has added its 24th million in 2 years, 9 months and 2 days - the first time that a million people has been added to Australia's population in less than 3 years.
Previously it has taken a time span of around 4 and a half years to reach each additional million from 1954 when the population hit 9 million until 2003 when the population hit 20 million.
And 17 years ahead of schedule
When Australia's population reached 19 million on 18 August 1999, the factors of population increase were such that the forecast was for the national population to reach 24 million in 2033.
However, rather than each new million being added every 7 to 9 years as was forecast based on the trends at the time, Australia is adding an extra million every 3 years - increasing from 21 million to 24 million in 8 years and 8 months.
Baby boom, longevity boom and migration growth - the main factors
Not only has the fertility rate over the last decade been much higher than predicted (and the consequential record baby boom averaging 300,000 births per year), but the increase in life expectancy was also beyond these predictions.
While net migration numbers have been slowing over the last couple of years, growth from migration was, and still is above the forecasts of the late 20th Century.
'Each of those 3 factors has been sustained, birth numbers are around 3000 - a number well up on what we used to see. Longevity continues to increase and people are living longer, and thirdly and mainly because skills demand sustained migration numbers in the time of an aging workforce, there haven't been local skills to be able to sustain labour growth in lots of sectors and so it's those skill migration visas that have been sustained for a couple of decades,' Mr McCrindle said.
40 million by 2050
As recently as 2009 the forecast was for the population to reach 36 million by 2050.
However, even based on the more modest population growth rate of 1.5% (well below the highs of 1.9% achieved in recent years), Australia's population will reach 40 million by mid-century, with the possibility of it being beyond 43 million (based on 1.7% annual growth).
'This is a realistic forecast and that keeps in mind some of the slowing growth areas that we're seeing at the moment and what it tells us is that we can't just assume that we can slow population growth, births, longevity, skills visas etc.
'I think therefore we have to plan for it and ensure that we have investment and policy to make sure the growth that we are seeing adds to to the lifestyle that Australians expect than detracts from it,' Mr McCrindle said.
24 million of 7.3 billion
While Australia's population growth is significant in national terms, our new milestone of 24 million is small compared to the US population of 323 million.
And in a global context, Australia's share of the world's population is just 0.32% - less than one-third of 1%.
Who will be the 24 millionth Australian?
Based on McCrindle's analysis, the 24 millionth Australian is most likely to be a baby boy named Oliver, born in the early hours of 16th February, in the Western suburbs of Sydney.